1. Field of the Invention
The present invention relates to a fuel supply device, particularly to a fuel supply device that prevents undesired water entered into a fuel path from remaining therein with a simple structure.
2. Description of the Related Art
Conventionally, there are known outboard motors mounted with a multi cylinder engine, each cylinder of which is attached with a fuel injection device. In such outboard motors, the following arrangement is well known. That is, fuel, which is pressurized by a fuel pump and fed out through a fuel hose, is equally distributed and supplied to each of the fuel injection valves through a rail-like fuel supply pipe called a delivery pipe.
A patent document 1 discloses the following arrangement. That is, a fuel supply device for outboard motors is provided with a fuel transfer pipe for supplying fuel from a fuel pump and a return pipe for returning excess fuel to a sub tank being attached at one end and another end of the above-mentioned rail-like fuel supply pipe, respectively. According to this arrangement, water entered into the fuel supply pipe from a fuel transfer pipe is sucked into the fuel injection valve along with the fuel. Even when the water is not sucked into the fuel injection valve, since the water is returned into the sub tank along with the excess fuel, it is possible to prevent the water from remaining within the fuel supply pipe.
A patent document 2 discloses the following arrangement. That is, in the fuel supply device for outboard motors, a fuel pump and a pressure regulator are disposed within a case of a vapor separator for separating vapor included in the fuel thereby eliminating a pipe necessary for returning excess fuel from the fuel supply pipe. According to this arrangement, no return structure including a return pipe is needed and a fuel supply system is simplified.
[Patent document 1] Japanese Published Unexamined Patent Application No. H10-176621
[Patent document 2] Japanese Published Unexamined Patent Application No. H10-218089
However, in the fuel supply device disclosed in the patent document 1, although there is no possibility that water entered into the fuel supply path remains within the fuel supply pipe, there are such disadvantages that an installation space for the return structure including the return pipe is needed and the cost for component parts and the number of man-hours are also increased.
In the art of the patent document 2, since no outlet of the fuel is provided other than the fuel injection valve, it is preferred that such an arrangement is provided that, when water enters into the fuel path, the water is reliably sucked from the fuel injection valve. However, the fuel supply device disclosed in the patent document 2 is not provided with such the arrangement.